This invention relates generally to disposable absorbent articles and more specifically to disposable absorbent articles, e.g., diapers, which exhibit enhanced liquid absorption and trapping characteristics.
Disposable absorbent articles, e.g., diapers, catamenial pads, panty liners, shields, etc., frequently make use of a liquid absorbent core located between a top-sheet and a back sheet. The top-sheet is commonly formed of a material which is pervious to body fluids, e.g., urine, to promote the transfer of such fluids into the core with minimal fluid retention by the top-sheet. The back-sheet is commonly formed of a liquid impervious or hydrophobic material to form a barrier wall so that any fluid absorbed by the article cannot escape out the back-sheet. In many cases, a fluid xe2x80x9cacquisition,xe2x80x9d xe2x80x9csurgexe2x80x9d or xe2x80x9ctransferxe2x80x9d layer is located between the top-sheet and the core to facilitate the transference of body fluid(s) into the core.
In some applications the top-sheet of the disposable absorbent article is formed a woven, non-woven or carded fibrous web. In other cases a perforated or apertured polymeric film is used in place of the fibrous web top-sheet. Typically most of such apertured films are of a three dimensional nature, e.g., they are embossed and/or debossed to include numerous protuberances, channels, capillaries, hills and valleys, etc. Such three dimensional apertured film top-sheets exhibit a pleasing soft, cloth-like appearance similar to that of the prior art woven, non-woven or carded fibrous webs, while providing for a quick and efficient transfer of liquid therethrough to the underlying absorbent layer(s).
Examples of perforated three dimensional film top-sheets are found in U.S. Pat. No. 3,929,135 (Thompson), U.S. Pat. No. 4,324,246 (Mullane et al.), U.S. Pat. No. 4,327,730 (Sorensen), U.S. Pat. No. 4,463,045 (Ahr et al), U.S. Pat. No. 4,552,709 (Koger et al.), U.S. Pat. No. 4,601,868 (Radel), U.S. Pat. No. 4,609,518 (Curro et al.), U.S. Pat. No. 4,629,643 (Curro et al.), U.S. Pat. No. 4,690,679 (Mattingly, III et al.), U.S. Pat. No. 4,806,411 (Mattingly, III et al.), U.S. Pat. No. 5,514,105 (Goodman et al.), D362,120 (Suskind et al), and D364,040 (Suskind), and in United States Statutory Invention Registration H1575 (Daugherty et al.).
The absorbent core of many disposable diapers and other higher performance incontinence products, e.g., adult briefs, typically have cores with enhanced absorbency capability. This enhanced absorbency can be accomplished by use of an air-laid super absorbent material, or by the inclusion of absorbency enhancers, e.g., materials sometimes referred to as xe2x80x9csuper-absorbent-polymersxe2x80x9d (which may be in the form of particles or fibers) with other absorbent materials, such as a fluff, e.g., comminuted wood pulp or other cellulosic fibers. Examples of super absorbent materials are hydrogel polymer particulates, sometimes referred to as xe2x80x9cSAP,xe2x80x9d and hydrogel polymer fibers, sometimes referred to as xe2x80x9cSAF.xe2x80x9d The fluff for the core serves as a means for quickly absorbing the liquid transferred to it. Unfortunately, while fluff is suitable for the task of quick absorption it is somewhat deficient from the standpoint of liquid retention and ability to accommodate repeated insults. SAP on the other hand, has the ability to retain absorbed liquid and to handle repeated insults. The drawback with SAP and SAF are their slowness in absorbing liquid. Accordingly, heretofore disposable absorbent articles have typically taken two approaches to ensure efficient action. In particular, they have included a higher ratio of SAP to fluff to facilitate the rapid absorption of the liquid by the fluff of the core until to SAP can absorb and trap it, and have also included an the heretofore mentioned acquisition or surge layer (also sometimes called a xe2x80x9ctransferxe2x80x9d layer) disposed over the core. Acquisition layers have typically been constructed of a woven, non-woven or carded fibrous material. They are arranged to quickly absorb the liquid through the absorbent article""s cover stock, liner, or top-sheet for temporary retention (e.g., to act as a temporary reservoir), and to transfer that liquid into the underlying core at a rate at which the core can absorb for final or permanent retention. In particular, an acquisition layer improves xe2x80x9cwickingxe2x80x9d of the absorbent article by spreading the body fluid in the xe2x80x9cxxe2x80x9d and xe2x80x9cyxe2x80x9d plane over the area of the core encompassed by the acquisition layer while also carrying the fluid in the xe2x80x9czxe2x80x9d direction to the core.
Examples of prior art acquisition layers are disclosed in U.S. Pat. No. 4,988,344 (Reising et al.), U.S. Pat. No. 4,994,037 (Bernardin), U.S. Pat. No. 5,294,478 (Wanek et al.), U.S. Pat. No. 5,300,054 (Feist et al.), U.S. Pat. No. 5,304,161 (Noel et al.), U.S. Pat. No. 5,387,208 (Ashton et al.), U.S. Pat. No. 5,460,622 (Dragoo et al.), U.S. Pat. No. 5,486,167 (Dragoo et al.), U.S. Pat. No. 5,520,673 (Yarbrough et al.), U.S. Pat. No. 5,522,809 (Larsonneur), U.S. Pat. No. 5,558,655 (Jezzi et al.), U.S. Pat. No. 5,591,149 (Cree et al.), U.S. Pat. No. 5,607,414 (Richards et al.), U.S. Pat. No. 5,609,588 (DiPalma et al.), U.S. Pat. No. 5,730,737 (Widlund et al.), U.S. Pat. No. 5,752,945 (Mosley et al.), U.S. Pat. No. 5,833,678 (Ashton et al.), U.S. Pat. No. 5,843,055 (Seger), U.S. Pat. No. 5,855,572 (Schmidt), U.S. Pat. No. 5,895,379 (Litchholt et al.), and U.S. Pat. No. 5,906,602 (Weber et al.). Examples of commercially available materials used for acquisition layers in disposable absorbent articles are through-air bond staple fibers, adhesively bonded staple fibers, and thermally point bonded staple fibers.
As will be appreciated by those skilled in the art increasing the SAP (or other absorption enhancing material) to fluff ratio to provide an absorbent product, e.g., diaper, suitable for accommodating multiple insults of body fluids would concomitantly place an additional burden on the liquid acquisition layer to facilitate transfer of the liquid at a rate that the SAP/other absorption enhancing material could accommodate. Heretofore the materials making up the prior art liquid acquisition layers have provided less than desired results.
Accordingly a need exists for a diaper or other high capacity absorbent article making use of a relatively high SAP/other absorption enhancing material content core and an effective liquid acquisition system to transfer the liquid into the core.
Various absorbent articles which are commercially available have made use of various layers of materials. For example, sanitary pads made by The Kendall Confab Retail Group and sold under the trademark EVERYDAY PANTILINER have included a top sheet formed of a fibrous material over the marginal edges of the pad, but not over the intake or xe2x80x9ctargetxe2x80x9d zone (i.e., the area at which the body fluid(s) gain(s) ingress into the absorbent article), a three dimensional apertured film forming the top layer of the intake/target zone, a fluid acquisition layer formed of a fibrous material (non-woven) web, and a core formed of an air laid web containing super absorbent material. Other pads in the form of Ultra Thins are also made by The Kendall Confab Retail Group and sold under trademark FRESH TIMES have included a top sheet formed of an apertured film, an air-laid acquisition layer and a core formed of a combination of air-laid and SAP or an air laid super absorbent material. Still other pads in the form of Contour Maxi pads are made by The Kendall Confab Retail Group and sold under the trademark FRESH TIMES have included a top sheet formed of an apertured film and a core formed fluff. Still other pads in the form of Maxi pads are made by The Kendall Confab Retail Group and sold under the trademark FRESH TIMES have included a top sheet formed of a fibrous material, a tissue fluid acquisition layer and a core formed of fluff. Diapers made by The Kendall Confab Retail Group and sold under the trademark HAPPIES have included a non-woven top sheet, a through-air-bonded (or non-woven) acquisition layer, a tissue layer, and an absorbent core made of fluff and SAP.
While all of the foregoing articles are suitable for their intended purposes, they never the less leave something to be desired from the standpoint of fluid retention capacity and fluid transfer into a high capacity core.
A disposable absorbent article, e.g., a diaper, which is arranged to be worn by a person to trap and collect fluid waste products, e.g., urine. The absorbent article is suitable for accommodating multiple insults of such fluid(s) without leakage, while also exhibiting good strike-through and re-wet properties.
The absorbent article basically comprises a top-sheet, a fluid acquisition system, and an absorbent core. The top-sheet includes a portion which forms the fluid intake or target zone of the absorbent article, with that portion of the top sheet being formed of a liquid pervious, e.g., hydrophilic, material. The fluid intake or target zone makes up a portion of the area of the absorbent core. The absorbent core is formed of a material suitable for accommodating multiple insults of the fluid waste products, e.g., comprises fluff and super absorbent materials for good fluid retention.
The fluid system comprises a first fluid acquisition layer and a second fluid acquisition layer. The first fluid acquisition layer is located below the fluid intake zone portion of the top-sheet and over the second liquid acquisition layer. The first liquid acquisition layer is formed of an apertured film, e.g., a three dimensional apertured film. The second fluid acquisition layer is formed of a fibrous, fluid pervious material, e.g., a non-woven. The second fluid acquisition layer is located over the absorbent core. At least one of the first and second acquisition layers is at least coextensive in size with the fluid intake zone.
The fluid acquisition system cooperates with the core to facilitate the transference of fluid, e.g., urine, into the core for absorption and retention in the core even under repeated insults.
When the absorbent article is in the form of a diaper it also preferably includes a back-sheet formed of a fluid impervious material.